Telephone system



Dec. 13, 1932. B. A. WAL LACE 1,890,479

I TELEPHONE SXSTEM Filed Feb. 21, 1930 2 Sheets-Sheet l r 7 ZZZ/2272271" fiEWfiiZli/Zi [E Dec. 13, 1932. B. A. WALLACE 1,390,479

' TELEPHONE SYSTEM Filed Feb. 21. 1930 2 Shuts-Sheet 2 22227527171 1 fiFfi/MZ/aiam Patented Dec. 13, 1932 UNITED STATES a. WALLACE, or CHICAGO, IL I NoIs, assrcnon 'ro KELLOGG swITcH oARn AND P ENT. OFFICE.

sunny comm, or CHICAGO, rumors,- A CORPORATION OF rumors '1ELEPHO1\IESYSTEM Application filed Iebruary 21, 1930. Serial No. 430,348.

My invention relates totelephone systems and more particularly to an improved attendant station circuit of the type used in ofiice buildings, hotels, etc. and to intercom munication between such an attendant station and corresponding main exchanges.

A feature'of my invention is the provision of means whereby an incoming call from a main exchange may either be answered directly by the called partly without the interception of the attendant, or ma be handled by the latter in the absence 0 the former.

Another feature of my invention is the provision of means whereby one or more incoming calls from one or more main exchanges may, be held over for a length of time until answered either by the called party or by the attendant.

A further feature of in circuit is the provision of improved signal ing means wherebythe attendant is kept informed as to the p r0' ceeding ofthe call .and the normal condition of the circuit. e 1 i A still further feature of my inventionis the provision of a special converting trunk circuitby means of which at timesrwhen the attendant stationand the extension stations I associated therewith are idle, as for instance at nights and at holidays, an incoming call may be automatically redirectedinto another main exchange communicating with an active attendant station afliliated with said first idle attendant station.

The abo effea-tures as well as others will be more specifically hereinafter described in the ensuing specification .and the accompanying drawings of which:

Fig. 1 illustrates the attendant stationjof my invention and Fig. '2 the converting trunk. circuit. Referring more in detail to Fig. 1, I have illustrated an attendants station circuit AS,

a pair ofswitching keys S and S said keys communicating through respective lines L,

L L and L with two corresponding-main exchanges of which only one, namely is shown in the drawing. The apparatus. shown at M comprises a line circuit composed of a line relay LR, a cut-01f relay'QO, and [a line lamp P. A portion of a cord circuit is also shown namely a ringing key BK, operable to connect the ringinggenerator G to theline and a battery supplyrelay BS. An extension phone E and an attenclants phone D are shownassociated withthe attendants circuit AS. The latter. consists of a ringing relay.

RR, a control relay CR, a ringingdisconnect relay DR and two holding relays R and HR.

A number of interconnected answering keys K, K, K etc. are also shown, each of which is intended to be associated Witha respective mainexchange such as M. The variousfunctions of this apparatus will be more readily understood 'from a description of the procedure followed and theoperations effected in connection with one or more incoming calls.

Upon the operation of ringing key RK ringing current from the generator Gr asso: ciated withthe exchange M will be transmitted in the usual manner through the jack J, the lines L and L the key S and the lines L and L tothe taps T and T? of the attendants circuit AS. The taps T andQT coinmunicate on one side with the answering key K through the leads land 5 and on theothen ringing current, therefore would ring the bell of the extension phone and operate relay RR, but not relay DR which requires direct current for itsoperation. By closing its alter nate contact 17 relay RR actuates the buzzer B over a circuit traced from the battery through buzzer B, "alternate contact 17 ,to. ground. Said contact 17 is a spring contact closing only during the ringing intervals. 1

, By closing its lower contact 19 therelay RR lights, the line lamp Z over a circuit leadingfrom the battery through lamp Z, lead 21, closed contact 19, lead 22, normal -contact 17 Z lighted after the ringing period. If now the called party at E answersthe callfhe will thereby, bylifting the recelver and cl-osmg switchhook contacts 23, energize the ringing disconnect relay DR overthe circuit pre:

viously indicated for-the ringing'eurrent,'the I o p relay HR from the "lineyo'lta'ge "ove a closed contacts of the ringing key BK and winding of the battery supply relay BS. closing its alternate contact 24 relay DR w ll energize relay OR, the "correspondlngcir cuit leading from the battery through relay CR, leads 2 5 and 26; alternate contact 24 "of relay-DR to "ground; By attractmgns armature'25 relayCR'will restore contact 19 of relay to "normal thus extinguishing the line la 'P Theen'e'rgiza'tionof CR will also light the'busy signal lamp Z "'overa circuit 7 traced from thefbatte'ry'through'lamp Z leads 20 and 47 normal contact-27' of relay lead 28, alternate contact 29 of relay CR to 7 ground. Finally by openingits'contact's 10 and T14 relay GR interrupts the energizing circuit of relay RR as previously traced'and prevents the operation of relay RE should ringing. current again beapphed-tothe lines After the conversation has been finished, the 'cal'led'party at E replaces"the recelver and thereby interrupts the circuit;- for *rel'ay DR and the latter restoring causes a similar interruption of the energizing circuit of recan by' throwing inthe' 'an'sweririg key-K will therebyefi'ectthe usual disconnect signal thereby'connecting' her"own-phoneto the line and energizing relay CR over a circuit traced from the-battery,-relay cR lead 25, no mal Y contact 31 'of relay 'R,-*l'ear132, contact 33 of key Kro' grouna. In the same manner a'sindicate'd before relay CR' will-restore Contact 19 ofr'elay RR to normahextinguish the line lamp l and light the lamp Z as a busysgnal.

' When the attendant;having'given the necessary information,-"replaces her recei-ver," she t'o the niain exchange b interrupting the energizing circuit of relay 'BS, but rela and the busy signal lamp.' 'L willrema'in energized until the ans'wering' 'key 'K'is; 'r'estored to normal. The latter action' will turn "revert the entire "systemto' normal by deenergi'zin'g'relay' GR. If, before the-key K is restored to normalfasecond call comes in, over the same line; said second callwill actuate the bellf'of theattendants' phone as Sh'ouldthe'attendantdesire tohold ma nection after answering the same she will first actuate the holding key HK and then restore the answering key K to disconnect the 'attendants phone D to permit her to answer other, calls during the holding period. The first of the se yvill,gnieyrg'rqe over relay R, key BK, lead 34, normal contact U11, tlfrfg" a w l itoriginal circuit which may be traced from tap T over lead 9, normal contact 10 of relay CR,

-leads ll; and 3fi5galternate,contact 37 of key K, lead 38, relay HR; lead 89, closed contact 41 of relay Rf, lead 423 normal contact;- 140i a portion of it'sp-reviou'senergizingecircuit;

to compensate for the-opening o keygK iand at the -same ft-ime', bytigbeing'energized: from the linen 'preventsa disconnect signal-to the the battery through lampl, 'lead '2O alternate-contact 43 of-relay R to'gr'ound. If new the party at the cxtension ph-one :15.

answers the call, bylifting 'his: 1'eceiver;a=he

will energize relay previously forth. The latter will-break the previously;

traced energizing circuit of relay. R at icon-- tact 24;,thu-s de nergizin also'relay HRr 0n the other hand it will energize relay-GR and;

restore the' original energizing circuit-of the busy signal lamp Z whose subsequentie1i-* er izi ng-circuit h ad beenc brokeh wit hthen-elease of "relay R. It "will alsofflactuate. the

holding buzzer B "to "announce 't'ha't th'e 'eX-Y tension party has answered thewcall andvtd elicit from *the attendant the' release of thehold ng key- 'HK, the "correspondingfcircuit leadingfrom the batterygithroughbuzzer TB;

mal contact 43 of relay "R nae-1i mal :v

Contact 27 of relay HR, lead28; 'contact'29' of relay GR tov'ground. release "of the holding key tendant the system one normal. I

l T'he' party =at'-th'e extension wphone' Egcan originate a call in the usualmannenlbyfliftei ng h s receiver thus "automatically. energiz in'gthe line relay LR at excl'i'angeM andlight- Vith he ore "reverts ing the'line lamptl as iazfsign'al' to the @pemwr;

The'corresponding.circuit' can'betraced f the battery through relay"LR,- lines-3.L L 1 relay DR iwhich is-,=energi -zed-, "lead "7',"- -1 d'uct'ion coil z', alternate 'sw'itch'hook contactzi 23 line '8, tap lines :Lianda-Ifif 'toi'iground atlower contact-efre'layiCO. {Th -above.

. ferred to energizationofrei ay DR c'angg tghn ground. The energization of relay CR brings the lamp Z to glow as a busy signal, the corresponding circuit being traced firom the ground and battery, through lamp Z, leads 20 and 47, normal contact '27, lead 28, closed contact 29 to ground. Theattendant at D can also place a call at exchange M by closing the key K and lifting her receiver, thus closing a circuit across the taps T and T for the energization of line relay LR and lighting the signal lamp Z said circuit comprising tap T, leads 4 and 91 across key K, induction coil '5, switchhook Contact 92, lead 93, key K, and lead 5 to tap T While I have shown only one attendant circuit associated with the lines L and L coming in from the main exchangeM, a number of such attendant circuits provided with the respective extension phones E, E etc. not shown in the figure and connected in parallel a with respect to the lines L and L may beinstalled.

All of which may be controlled by the same attendant and have a common buzzer B and an individual holding buzzer B to indicate that the particular extension party for whom the call has'been held has I answered and that the holding key should be restored.

A similar system may be carried out in connection with calls coming in from other main exchanges through the keys K, K etc.

In the drawings I have shown four terminals, A, B, C, D associated withthe keys S and S ythese being the terminals of the converting trunk circuit shown in Fig. 2.

At times when the aggregate of attendant and extension stations such as AS, E, and others, not shown in the figure, located in the same building or office are not being operated, for instance at nights and on holidays, it

. may be desirable to have the calls coming in from a main exchange such as M redirected to another active attendant station associated with anothermain exchange such as M shown in Fig. 2, said second attendant station being affiliated withthe first, for instance by virtue of belonging to the same concern;

For the purpose of automatically transferring an incoming call either from main ex change Mto main exchange M or from the latter to the former the converting trunk circuit CT shown in Fig. 2'is provided. It is thrown into operation by shifting the switching keys S and S which may be combined into a single et-pole switch, so that the lines L L L and L connecting the attendant station with the main exchanges Mand M are disconnected, and the lines L L L and L leading to the terminals A, B, C and D01 the converting trunk circuit CT are connected instead.

When the'operator at exchange M plugs the cord P into the jackJ and operates the I ringing key RK ringing current istra-nsmitted from Gwhichenergizes ringingrelayRR of the converting trunk circuit CT over a on:-

cuit traced from the generator G" and its ground, alternate contact ofRK and L repeating coil 0 lead 51, relay RR, lead 52,

condenser 53, repeating coil 0*, line L to the ring side of the line through jack J and plug P, alternate contact of RK to the ground associated therewith. The construction of switch S is such that when relay RR is-energized and attracts its armature 68, contact 54 closes and remains .closed until restored the battery and winding of relay ll, lead 59,

contact 57, lead 60, contact 58 to ground."

Relay 11 in turn provides for the energize tion of the holding relay HR over a'circuit leading from the battery through relay HR,

By closing its contact 63, relay HR completes a locking circuit for itself and ener gizes the line relay LR of the exchange M which'in turn lights the line lamp Z .as a signal to the'operator at the main exchange M, the corresponding circuit leading fromthe battery and relay LR through contact 64 of relay CO, lines L and L, repeating coil C, lead 65, alternate contact 63 and upper wind ing of relay HR, lead 66, repeating coil G lines L and L to ground at contact .67 of relay CO. The operator at exchange M noticing the glow of lamp Z will insert the plug P into the jack J as a result of which thecutoli relay GO isenergized openingits contacts 64 and 67. Goncomitantly. an energizing circuit for relay 8 of the converting trunk circuit is established which may be traced from the battery and winding of relay BS of exchange M over ringing key RK, the ring contact of plug P, line L repeating coil C lead 69, relay 8, closed contact 7 O of relay 9 a to ground. Relay 8 by; closing its contact 71 i throws release relay R stores contact 5d of switch S to normal.

into operation which, through its armature 55 mechanically re Since said contact 54' forms a link in the enerlead 61, contact 62ofrelay 11 to'ground. f

said relay LR and'the ground of relay G now disconnected, the battery and ground 0t rrela'y BS are substituted through the corre- 'sponding part of the cord circuit. By keeps ing its contact 7 2 closed relay HR causes the operation'of relay BS at M togive supervision of the call to the operator at exchange 'M, over a circuit which can be traced fronr the tip side of the cord, line L, repeating coil C lead 74, resistance recontact 72 of relay HR, lead 75, normal contact 7 Got relay 9, lead 77, repeating coil, 0*, line L to the ring side of the cord plug P. In the meantime conversational facilities have been established tor the stations associated with the exchanges M and vM over their respective cord-c1rcu1ts,tanswering and calling plugs P and P and" the heavily outlined conductors I of-the conver-ting trunk circuit, including the repeating'co ls. I

' When afterthe' end of the conversation the operator at exchange M withdraws her plug P the energizing circuit of the holdingrelay HRis broken and:by opening contact 72 of thenpreviously'traced supervisory circuit a disconnect signal is given to the operator of exchange M" who. also withdraws her plug and the entires'ystem reverts to normal.

7 Having described the procedure and operation-in connectionwith acall coming inbyl thewayof exchange M I shall now do the sameuwith reference to a call coming in "from exchange M. Similarly tothe preceding case the operator at exchangeM inserts her call: ing plug. P and'sends ringing current through the system which actuates relay RR? over a circuitltraced' from .theringing generator G and its ground, ringing lreyRK, plug P, lines L and L repeating coil C, lead 78, relay EH lead 7 9, condenser 80,; repeating coil 0 line L to ground at alternate contact of the p ringing key. BK. By closing contact81 relay provides a path for the energizing current of relay '11 traced from the latters battery; and winding to ground at contact 81. Relay 11 in turn by closing its contact 62 provides for. the energization of relay HR- from the ,latters battery. By closing its contact 63, relay HR locks up over acircuit comprising ,the upper-half of its winding and origihating and ending in the battery and ground of relay BS of exchange Mas previously traced.- VBy closing itscontact 72, relay HR" provides for the lighting of the signal lamp Z through the energlzation of theline relay LR over a circuit traced from the, latters battery and winding over lines L and L,

repeating coil C lead .74, resistance r, contact 72 of relay HR, lead 75, normal contact 76 of relay :9, lead 77, repeating coil C line L to ground at contact at of relay C0 The operator at exchange M inserts her plug 7 P into the jack J as aresultof which a conversational circuit isestablished between the twoexchanges including their respective cord circuits, the heavily outlined conductors of the converting trunk circuit and the repeating coils. When the conversation is finished the a no answer from the latter,she withdraws her plug thereby deenergizing the above men and restoring the entire system to normal;

It has been pointed out that vat the time when the plug P is inserted relay HR locks fromthe battery of relay BS, the battery of relay Lfifbeing at this time disconnected through the simultaneous energization of relay CO; but when the operator at M Withdraws the plug relay CO is deenergized and the battery of relay LR is switched upon the said locking circuit of relay HR, without however preventing deenergization of the same because its'polarity is opposite to that of the battery of relay BS.

'Relays RE, 8 and 11 are copper sleeve relays for the usual purpose of retarding their by the resistances in'shunt with relay DB in Fig. l and relay 11 in Fig. 2. Resistance r in Fig. 2 being connected in'series with the repeating coils C and C through contacts 72 of relay HR and 76 of relay 9, serves to' prevent too high a magnetization of therepeating'coils by current from the exchange M when the operat'orat the latterconnects her plugto the line.

Havingdescribed my invention operatingwith a certain circuit arrangement, I do not ,deenergization. The same purpose is served wish to belimited to the same as chan es and modifications may readily suggest themselves to those skilledin the art, and I, therefore,-

aim to cover all such changes and modifications ascome within the spirit and scope of the appended claims.

Havingdescribed my invention, what I claim is new and desire to secure by United States Letters Patent is: v

1. A telephone'system including an at tendant-station circuit, an extension phone and an attendant phone, means whereby an incoming call may be answered directly at the extension phone and supervisory signalling means including means for, indicating the answering of thecall at the extension phone and'the termination of the call automatically controlled by said extension phone. I 2. An attendant station circuit communicating with a main exchange and including an extension phone, means for answering an incoming call, from said main exchangedi- 80v tioned relays extinguishing the line lamp Z v rectly at the extension phone, supervisory signalling means indicating the arrival of the call, and supervisory signalling means indicating the completion and the termination of the call, said supervisory signalling means controlled automatically by the called party at the extension phone.

3. An attendant station circuit including an extension phone and an attendants phone,

means for answeringoan incoming call directly at theextension phone, means for answerlng an 1ncom1ng call at the attendants phone, supervlsory signalling means announcing the arrival of the call automatice callycontrolled by the act of answering the call at any of said phones and supervisory signalling means announcing the process of prising relays controlled by the extension phone for holding said incoming call until answered by party at extension phone.

5. An attendant stationcircuit associated with a plurality of telephone exchanges and i including an extension phone and an attendant phone, means for answering an incoming call from any of said exchanges'dir'ectlyat the extension phone, means for answering the same at the attendants phone, manually controlled relay means for holding an incoming call until answered by the party at the extension phone, supervisory signalling means indicatingthe duration of the holding interval of said call and supervisory signalling means indicating the completion of said held call by the party at the extension phone.

6. A telephone circuit having two pairs of terminals and including a plurality of relays and sources of electric power some of said relays energized by an alternating ringing current coming in from one pair of terminals to operate other relays, said last relays operating to permit the flow of direct current through the other pair of terminals, and vice versa.

7 A telephone circuit of the character described including a plurality of relays in combination, interposed between a main exchange A and a main exchange B, one of said relays energized by a ringing current from exchange A to cause the energization of a holding relay, said last relay having a holding winding energized by direct current from exchange A and a holding contact forming a link in a direct current circuit associated atedwith exchange A i 1 10. A transfer.

Aland .a' main exchange B and comprising a plurality of relays in combinationpone of said relaysenergizedby ringing current from m'aln exchange B tocause the energizatlon of a holding relay through the instrumem, tali-ty of ot-herrelays, said holding relayjhav- V ingla secondary holding winding -'forming a link. in a {direct current control circuit associ- 9, A telephone circuit fof the character described interposed: between a main exchange A and a mainexchang'esB including ahold-' ing relay auxiliary relays, said holding relay having a winding forthepurpose of an in tial energizatlon fromeither exchange A orexchjange B-through the instrumentality oi respectiyeauxiliary relays, and a locking winding for the pnrposefot maintaining in-- U .tact control and supervisory direct current circuits associated with exchanges A and B respectively,

ring circuit of the character described interposed betweenia mainlexchange A and a mainiexchange B including a holding relay initially energized either ity of respective auxiliary relays orfrom exchangeB through the instrumentalityof I from exchange A through the instrumentalexchanges A and B respectively and having a holding relay initially energized either from exchange A through the instrumentality of respective auxiliary relays operating solely during the ringing intervals or from exchange B through the instrumentality of respective auxiliary relays energized solely during the interval between the initiation of r the call from exchange B and the establish ment of a conversational circuit between ex changes A and B, sa1d holding relay having a secondary holding wind-111g subsequently change A, and a holding contact-forming a link in a direct current supervisory and signal circuit associatedwith exchangeB, dis-' connect means for revertmg sa1d transferrlng circuit and sa1d supervlsory circult tonor-' be initiated directly at the extension phone or at the attendant phone, and supervisory 115 energlz'ed by a controlling c1rcu1t.from.ex

Q mean sindicat-ing the answering of the'incom- I ing call atthe extension phone andthe tetv mination of the call said supervisory means automatically controlled by saidjexten'sion phone.

'13-. A telephone system including an attendant station circuit, an extension phone and anattendantphone', means whereby an incoming call may be answered directly .at

the extension phone or at :the attendant phone; and supervisory means'indicating the busy condition of said extension phone.

"14. A telephone systemincluding an attendant station circuit, an extension phone and an attendant phone, means whereby an incoming call may be answered directly at theextension phone or at the attendant o is phone, and supervisory means indicating the bnsy condition-of said extension phone automatically controlled by said extension phone.

Signed by me, at Chicago, in the county of 50 has 

